Copper alloy powder and preparation method thereof

Abstract

The invention discloses copper alloy powder and a preparation method thereof, and belongs to the technical field of alloy powder. The preparation method of the copper alloy powder comprises the following steps that S1, a copper alloy powder body is soaked in a passivation solution under the ultrasonic condition, then dried at the temperature of 40-60 DEG C and then heated to 80-100 DEG C to be dried, and a pre-passivation layer is formed; and S2, the dried copper alloy powder body is subjected to heat preservation at the temperature of 200-350 DEG C, then the temperature is increased to 350-450 DEG C according to the temperature increasing speed of 2-3 DEG C / min for heat preservation, then the temperature is increased to 800-1000 DEG C according to the temperature increasing speed of 5-10 DEG C / min for heat preservation, the heating atmosphere is vacuum or inert gas, and finally the passivation layer is formed. The prepared copper alloy powder can achieve long-term oxidation resistance.

Description

Technical Field

[0001] This invention relates to the field of alloy powder technology, specifically to a copper alloy powder and its preparation method. Background Technology

[0002] Copper alloys, with their excellent electrical conductivity, corrosion resistance, and decorative properties, are widely used in the manufacture of numerous products, including electronics, construction, packaging, and imitation gold. Taking brazing filler metal as an example, copper alloys are commonly used for brazing copper to copper alloys. They have extremely wide applications in 5G communication electronic equipment, traditional air conditioning and refrigerator refrigeration equipment, and the motor industry. In many cases, they can even replace silver brazing filler metal for brazing copper to copper alloys, resulting in brazed joints with high strength.

[0003] Currently, atomization is the primary method for preparing copper alloy powders, encompassing sub-types such as gas atomization, centrifugal atomization, and vacuum atomization. Among these methods, vacuum atomization has attracted significant attention due to its ability to produce copper alloy powders with good sphericity, a shorter technical process, relatively suitable cost, and low oxygen content. However, copper alloy powders prepared by vacuum atomization are highly susceptible to oxidation and discoloration in practical applications due to their large specific surface area. Especially in hot summers, copper-phosphorus, copper-phosphorus-tin, and copper-phosphorus-tin-nickel series powders will oxidize and discolor within just 2-5 hours of exposure to air. This phenomenon is not only extremely detrimental to powder storage but also negatively impacts their subsequent use. For example, when used for brazing, if the powder surface oxidation is too high, technical problems such as poor solder-substrate wetting and poor welding performance will occur.

[0004] In addition, metal powder, as the basic raw material for laser additive manufacturing, plays a crucial role in the absorption rate of laser light, which directly affects the quality and performance of the formed parts.

[0005] Alloying is also an attempt to improve laser absorption rate. Studies have shown that adding certain alloying elements can change the laser absorption characteristics of copper alloys. For example, in Cu-0.8wt%Cr powder, due to the distortion caused by Cr solid solution in the Cu lattice and the high light absorption value of Cr itself, the laser absorption rate of this alloy powder at 1064nm reaches 30.5%, which is higher than that of pure copper powder with the same particle size distribution. Therefore, how to improve the laser absorption rate of copper alloys is also a problem that needs to be solved by existing technologies. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a copper alloy powder and its preparation method, thereby solving the technical problem of how to improve the oxidation resistance of copper alloy powder in the prior art.

[0007] To achieve the above-mentioned technical objectives, the present invention provides a method for preparing copper alloy powder, comprising the following steps:

[0008] S1. The copper alloy powder body is immersed in a passivation solution under ultrasonic conditions, then dried at 40℃-60℃, and then heated to 80-100℃ to dry to form a pre-passivation layer; the passivation solution is an aqueous solution containing silane coupling agent and titanate coupling agent;

[0009] S2. The dried copper alloy powder body is first kept at 200℃-300℃, then heated to 350-450℃ at a heating rate of 2℃ / min-3℃ / min and kept there. After that, it is heated to 800℃-1000℃ at a heating rate of 5-10℃ / min and kept there. The heating atmosphere is a vacuum or inert gas, and finally the passivation layer is formed.

[0010] In any embodiment, in step S1, the passivation solution further contains acetylacetone, and the mass concentration of acetylacetone in the passivation solution is 0.5%-1.5%.

[0011] In any embodiment, in step S1, the immersion temperature is 20°C-30°C, and the immersion time is 10-30 minutes.

[0012] In any embodiment, in step S2, the holding time at 200℃-300℃ is 1-2 hours; and / or, in step S2, the holding time at 350-450℃ is 1-2 hours; and / or, in step S2, the holding time at 800℃-1000℃ is 2-3 hours.

[0013] In any embodiment, in step S2, the temperature is increased to 350-450℃ at a heating rate of 2℃ / min-3℃ / min and held at that temperature, and then increased to 800℃-1000℃ at a heating rate of 5-10℃ / min and held at that temperature.

[0014] In any embodiment, in step S2, the vacuum degree during the heat preservation stage of 200℃-300℃ is 1×10⁻⁶. -2 Pa-1×10 -1 The vacuum degree is 1×10 Pa during the heat preservation stages of 350-400℃ and 800-1000℃. -3 Below Pa.

[0015] In any embodiment, in step S1, the passivation solution is an aqueous solution containing a silane coupling agent and a titanate coupling agent, wherein the concentration of the silane coupling agent is 10%-15% and the concentration of the titanate coupling agent is 2%-5%; and / or, the pH of the passivation solution is adjusted to 4-6.

[0016] In any embodiment, in step S1, the silane coupling agent is one or both of aminosilane and vinylsilane; the titanate coupling agent is a monoalkoxy titanate.

[0017] In any embodiment, in step S1, the copper alloy powder body contains the following mass percentages of Cu, Cr, Zr, Al, Ni and Mo: Cr: 0.8%-2.5%, Zr: 0.05%-0.5%, Al: 0.1%-0.8%, Ni: 0.2%-1.5%, Mo: 0.2%-1.5%, with the balance being copper and unavoidable impurities.

[0018] In addition, the present invention also proposes a copper alloy powder, which is prepared by the above-described preparation method.

[0019] Compared with the prior art, the beneficial effects of the present invention include: the silane coupling agent and titanate coupling agent in the passivation solution can promote uniform penetration of the coupling agent during ultrasonic impregnation, forming the basic framework of the pre-passivation layer on the surface of the copper alloy powder; the siloxane groups (-Si-O-) of the silane coupling agent undergo hydrolysis and condensation to form a continuous SiO2 enriched network; the titanate coupling agent's titanium oxide bonds (-Ti-O-) combine with the hydroxyl groups (-OH) on the copper surface and interweave in the silicon oxide network, forming a "Si-Ti-O" composite skeleton. Subsequent step-by-step drying (first evaporating free water at a low temperature of 40-60℃, then removing bound water at 80-100℃) avoids the micropores in the layer caused by rapid water evaporation, thereby increasing the initial density of the pre-passivation layer and initially blocking the direct contact channel between oxygen and the copper substrate. The multi-stage heating process in step S2 (200-300℃ → 350-450℃ → 800-1000℃) is key to improving the stability of the passivation layer. This is achieved through gradual strengthening of interfacial chemical bonds via temperature gradient control: Holding at 200-300℃ promotes the slow decomposition of residual organic groups (such as amino and vinyl groups) in the coupling agent, reducing impurity voids within the layer, while simultaneously allowing silicon and titanium to initially form weak coordination bonds (Cu-O-Si, Cu-O-Ti) with the copper surface; Holding at 350-450℃ prevents layer cracking caused by thermal stress. At this point, the alkoxy groups (-OR) of the titanate ester are completely hydrolyzed, and Ti... 4+ With Cu 2+ The coordination effect is enhanced, and the interface between the composite framework and the copper substrate is more tightly bonded. High-temperature treatment at 800-1000℃ causes trace diffusion of silicon and titanium elements into the copper surface, forming a dense passivation layer with a thickness of 10-20nm. This layer has a porosity of ≤0.5%, which significantly reduces the oxygen permeation rate. This allows the passivation layer to both physically block oxygen and prevent detachment through stable chemical bonding, ultimately achieving long-term oxidation resistance (oxygen increase ≤40ppm per year at 35℃ and 80% humidity). Detailed Implementation

[0020] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60–120 and 80–110 are listed for a specific parameter, it is understood that ranges of 60–110 and 80–120 are also expected. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5. In this application, unless otherwise stated, the numerical range "a–b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0021] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0022] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0023] This specific embodiment also proposes a method for preparing copper alloy powder with a passivation layer, including the following steps:

[0024] S1. The copper alloy powder body is immersed in the passivation solution for 10-30 minutes under ultrasonic treatment at an immersion temperature of 20℃-30℃, followed by drying at a low temperature of 40-60℃ for 1-2 hours (slowly evaporating free water), and then heated to 80-100℃ for another 1-2 hours to form a pre-passivation layer; the passivation solution is an aqueous solution containing a silane coupling agent and a titanate coupling agent, wherein the concentration of the silane coupling agent is 10%-15% and the concentration of the titanate coupling agent is 2%-5%; in some embodiments, the pH of the passivation solution is adjusted to 4-6; the silane coupling agent is one or both of aminosilane and vinylsilane; the titanate coupling agent is a monoalkoxy type titanate;

[0025] S2. The dried copper alloy powder body is first held at 200℃-300℃ for 1-2 hours, then heated to 350-450℃ at a heating rate of 2℃ / min-3℃ / min and held for 1-2 hours. Afterwards, it is heated to 800℃-1000℃ at a heating rate of 5-10℃ / min and held for 2-3 hours. The heating atmosphere is a vacuum or inert gas, ultimately forming the passivation layer. The vacuum degree during the 200℃-300℃ holding stage is 1×10⁻⁶. -2 Pa-1×10 -1 The vacuum degree is 1×10 Pa during the heat preservation stages of 350-400℃ and 800-1000℃. -3 Below Pa.

[0026] In some embodiments, the passivation solution further contains acetylacetone, wherein the mass concentration of acetylacetone in the passivation solution is 0.5%-1.5%. When the passivation solution contains 0.5%-1.5% acetylacetone, its ketone group (-CO-) can react with Cu. 2+ The formation of stable chelates serves two purposes: firstly, it guides the coupling agent to adsorb onto the active sites on the copper surface during the impregnation stage, preventing local thinning of the passivation layer; secondly, it inhibits the oxidation reaction of Cu during high-temperature treatment (the trace reducing groups produced by the decomposition of acetylacetone can consume surface oxygen), further reducing the generation of oxidation products.

[0027] In some embodiments, the ultrasonic impregnation power is 200-500W and the frequency is 20-40kHz.

[0028] This specific embodiment also proposes a copper alloy powder, which is prepared by the above preparation method.

[0029] Furthermore, in the copper alloy powder preparation method proposed in this invention, the SiO2-enriched phase formed by the hydrolysis and condensation of the silane coupling agent exhibits significantly higher absorption capacity for 300-1500 nm wavelength lasers than pure copper (SiO2 has a band gap of approximately 3.1 eV and can absorb ultraviolet to near-infrared lasers through electronic transitions); the tetravalent titanium (Ti) in the titanate coupling agent... 4+The TiO2 or copper titanate phases formed by these phases have a high absorption rate for laser light (TiO2 can achieve an absorption rate of over 60% in the visible to near-infrared band) and can form energy level complementarity with SiO2, thus broadening the light absorption range. The two phases are interwoven and distributed in the pre-passivation layer, initially breaking the high reflectivity of the pure copper surface. Subsequent staged heating treatment further improves the laser absorption rate of the copper alloy powder.

[0030] Acetylacetone makes the passivation layer more uniformly covered on the copper powder surface, avoiding high reflection points caused by local exposure; the trace carbon elements remaining after the decomposition of acetylacetone (existing in a graphite-like structure) can absorb laser energy through π electron transitions, forming a light absorption synergy with the oxides of Si and Ti, further improving the overall absorption rate.

[0031] The copper alloy powder body in this invention is derived from existing technology and can also be obtained by existing gas atomization methods.

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0033] In this invention, the terms "some embodiments," "this embodiment," and examples are used to describe a subset of all possible embodiments. However, it is understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with each other without conflict.

[0034] If the application documents contain similar descriptions such as "first / second", the following explanation shall be added: In the following description, the terms "first / second / third" are used only to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first / second / third" may be interchanged in a specific order or sequence where permitted, so that the embodiments described herein can be implemented in a different order than that described herein.

[0035] In this embodiment, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, object A and / or object B can represent three situations: object A exists alone, object A and object B exist simultaneously, and object B exists alone.

[0036] The copper alloy powder in the following examples or comparative examples contains the following mass percentages of Cu, Cr, Zr, Al, Ni and Mo: Cr: 2.1%-2.2%, Zr: 0.2%-0.3%, Al: 0.5%-0.7%, Ni: 0.8%-1.0%, Mo: 0.5%-0.6%, with the balance being copper and unavoidable impurities.

[0037] Example 1

[0038] This embodiment presents a copper alloy powder, which is prepared by the following steps:

[0039] S1. The copper alloy powder body is immersed in the passivation solution for 20 minutes under ultrasonic irradiation at a temperature of 25°C, followed by drying at a low temperature of 40°C for 2 hours (slowly evaporating free water), and then heated to 90°C for 1.5 hours to form a pre-passivation layer; the passivation solution is an aqueous solution containing silane coupling agent and titanate coupling agent, wherein the concentration of silane coupling agent is 12% and the concentration of titanate coupling agent is 3%; the pH of the passivation solution is adjusted to 4 by acetic acid; the ultrasonic irradiation power is 200W and the frequency is 20kHz; the silane coupling agent is aminosilane; the titanate coupling agent is monoalkoxy titanate;

[0040] S2. The dried copper alloy powder body is first held at 200℃ for 2 hours, then heated to 350℃ at a heating rate of 2℃ / min and held for 2 hours, followed by heating to 1000℃ at a heating rate of 5℃ / min and held for 2 hours. The heating atmosphere is inert argon gas, which ultimately forms the passivation layer. The vacuum degree during the 200℃ holding stage is 1×10⁻⁶. -2 The vacuum degree during the 350℃ and 1000℃ heat preservation stages is 1×10 Pa. -3 Below Pa.

[0041] Example 2

[0042] This embodiment presents a copper alloy powder, which is prepared by the following steps:

[0043] S1. The copper alloy powder body is immersed in the passivation solution for 30 minutes under ultrasonic irradiation at a temperature of 20°C, followed by drying at a low temperature of 50°C for 1.5 hours (slowly evaporating free water), and then heated to 100°C for 1 hour to form a pre-passivation layer; the passivation solution is an aqueous solution containing silane coupling agent and titanate coupling agent, wherein the concentration of silane coupling agent is 15% and the concentration of titanate coupling agent is 2%; the pH of the passivation solution is adjusted to 6 by acetic acid; the ultrasonic irradiation power is 300W and the frequency is 30kHz; the silane coupling agent is vinylsilane; the titanate coupling agent is monoalkoxy titanate;

[0044] S2. The dried copper alloy powder body is first held at 250℃ for 1.5h, then heated to 400℃ at a rate of 2℃ / min and held for 1h, followed by a heating rate of 8℃ / min to 900℃ and held for 2h. The heating atmosphere is inert argon gas, ultimately forming the passivation layer; the vacuum degree during the 250℃ holding stage is 1×10⁻⁶. -1The vacuum degree during the 350℃ and 900℃ heat preservation stages is 1×10 Pa. -3 Below Pa.

[0045] Example 3

[0046] This embodiment presents a copper alloy powder, which is prepared by the following steps:

[0047] S1. The copper alloy powder body is immersed in the passivation solution for 10 minutes under ultrasonic irradiation at a temperature of 30°C, followed by drying at a low temperature of 60°C for 1 hour (slowly evaporating free water), and then heated to 80°C for 2 hours to form a pre-passivation layer; the passivation solution is an aqueous solution containing silane coupling agent and titanate coupling agent, wherein the concentration of silane coupling agent is 10% and the concentration of titanate coupling agent is 5%; the pH of the passivation solution is adjusted to 5 by acetic acid; the ultrasonic irradiation power is 500W and the frequency is 40kHz; the silane coupling agent is aminosilane; the titanate coupling agent is monoalkoxy titanate;

[0048] S2. The dried copper alloy powder body is first held at 300℃ for 1 hour, then heated to 450℃ at a heating rate of 3℃ / min and held for 1.5 hours, followed by heating to 800℃ at a heating rate of 10℃ / min and held for 3 hours. The heating atmosphere is inert argon gas, which finally forms the passivation layer. The vacuum degree during the 300℃ holding stage is 1×10⁻⁶. -2 The vacuum degree during the 350℃ and 800℃ heat preservation stages is 1×10 Pa. -3 Below Pa.

[0049] Example 4

[0050] This embodiment proposes a copper alloy powder. The difference between the preparation method and that of Embodiment 1 is that the passivation solution also contains acetylacetone, and the mass concentration of acetylacetone in the passivation solution is 0.5%.

[0051] Example 5

[0052] This embodiment proposes a copper alloy powder. The difference between the preparation method and that of Embodiment 1 is that the passivation solution also contains acetylacetone, and the mass concentration of acetylacetone in the passivation solution is 1.5%.

[0053] Comparative Example 1

[0054] The difference between the preparation method of the copper alloy powder proposed in this comparative example and that in Example 1 is that the passivation solution does not contain monoalkoxy titanate, and an equal amount of aminosilane is used to replace the monoalkoxy titanate.

[0055] Comparative Example 2

[0056] The difference between the preparation method of the copper alloy powder proposed in this comparative example and that in Example 1 is that the passivation solution does not contain aminosilane, and an equal amount of monoalkoxy titanate is used to replace aminosilane.

[0057] Comparative Example 3

[0058] The difference between the preparation method of the copper alloy powder in this comparative example and that in Example 1 is that in step S2, the powder is kept at the same temperature. Specifically, the dried copper alloy powder body is first kept at 250°C for 5 hours in a vacuum or inert gas atmosphere to finally form the passivation layer.

[0059] Comparative Example 4

[0060] The difference between the preparation method of the copper alloy powder in this comparative example and that in Example 1 is that in step S2, the powder is kept at the same temperature. Specifically, the dried copper alloy powder body is kept at 1000°C for 6 hours in an inert argon atmosphere to finally form the passivation layer.

[0061] Related tests

[0062] Si and Ti concentration tests in the passivation layer

[0063] Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to dissolve the powder sample in a nitric acid-hydrofluoric acid mixed solution, and the concentrations of Si and Ti elements in the solution were measured and converted to ppm by weight in the powder.

[0064] Passivation layer adhesion test

[0065] The surface of the powder compact was scratched using a scratch tester (CSMRevetest) at a load rate of 5 N / min (maximum load 30 N). The critical peel load (N) was detected by acoustic emission signal to characterize the bonding force between the passivation layer and the substrate.

[0066] Laser absorption rate test

[0067] The reflectance in the wavelength range of 300 nm to 1500 nm was measured using a UV-Vis-NIR spectrophotometer (PerkinElmer Lambda 950), and the absorptivity was calculated (absorptivity = 1 - reflectance - transmittance, and the transmittance of the powder sample is approximately 0).

[0068] Oxygen concentration test

[0069] The oxygen, nitrogen and hydrogen were analyzed using an OH-836 analyzer. The powder was heated to a molten state under an inert atmosphere, and the oxygen content was determined by infrared detection. The results are expressed in ppm by weight.

[0070] Long-term antioxidant test

[0071] The powder was stored in a constant temperature and humidity chamber at 35°C and 80% relative humidity for one year. The oxygen concentration was measured periodically (0, 3, 6, and 12 months), and the oxygen increment (12-month oxygen concentration - initial oxygen concentration) was calculated.

[0072] The test results are shown in Tables 1 and 2.

[0073] Table 1. Si and Ti concentrations and bonding strength of copper alloy powders in Examples 1-5 and Comparative Examples 1-4

[0074]

[0075] Table 2. Results of laser absorptivity and oxygen concentration changes of copper alloy powders in Examples 1-5 and Comparative Examples 1-4.

[0076]

[0077]

[0078] Passivation layer composition and antioxidant properties: Examples 1-5 contain Si and Ti composite passivation layers, and the initial oxygen concentration (250-310 ppm) is significantly lower than that of Comparative Examples 1-2 (420-550 ppm). Moreover, the oxygen increase over 12 months (25-40 ppm) is much lower than that of the comparative examples (90-180 ppm), indicating that the synergistic effect of Si and Ti can enhance the antioxidant barrier.

[0079] Adhesion: The adhesion of the examples was significantly higher than that of Comparative Example 1 (single Si, 8N) and Comparative Example 2 (single Ti, 10N), and the adhesion of Examples 1-5 with segmented heating was better than that of Comparative Examples 3-4 (11-12N) with single-temperature heating, indicating that the composite components and segmented heating can enhance the interfacial adhesion.

[0080] Laser absorption rate: The absorption rates (57-65%) of Examples 1-5 and Comparative Examples 1 and 3-4 containing Si were higher than those of Comparative Example 2 without Si (35%), indicating that Si is the key to maintaining a high absorption rate; Example 3 had the best absorption rate (65%) due to its higher Ti concentration (150 ppm).

[0081] Examples 4-5 (containing 0.5-1.5% acetylacetone) have lower oxygen increment and higher binding force than Example 1 because acetylacetone can promote the coordination reaction between Ti and Cu matrix and optimize the compactness of passivation layer.

[0082] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing copper alloy powder, characterized in that, Includes the following steps: S1. The copper alloy powder body is immersed in a passivation solution under ultrasonic conditions, then dried at 40℃-60℃, and then heated to 80-100℃ to dry to form a pre-passivation layer; the passivation solution is an aqueous solution containing silane coupling agent and titanate coupling agent; S2. The dried copper alloy powder body is first kept at 200℃-300℃, then at 350-450℃, and then at 800℃-1000℃. The heating atmosphere is a vacuum or inert gas, and finally the passivation layer is formed.

2. The method for preparing copper alloy powder according to claim 1, characterized in that, In step S1, the passivation solution also contains acetylacetone, and the mass concentration of acetylacetone in the passivation solution is 0.5%-1.5%.

3. The method for preparing copper alloy powder according to claim 1, characterized in that, In step S1, the immersion temperature is 20℃-30℃, and the immersion time is 10-30 minutes.

4. The method for preparing copper alloy powder according to claim 1, characterized in that, In step S2, the holding time at 200℃-300℃ is 1-2 hours; and / or, in step S2, the holding time at 350-450℃ is 1-2 hours; and / or, in step S2, the holding time at 800℃-1000℃ is 2-3 hours.

5. The method for preparing copper alloy powder according to claim 1, characterized in that, In step S2, the temperature is increased to 350-450℃ at a heating rate of 2℃ / min-3℃ / min and held at that temperature, and then increased to 800℃-1000℃ at a heating rate of 5-10℃ / min and held at that temperature.

6. The method for preparing copper alloy powder according to claim 1, characterized in that, In step S2, the vacuum degree during the heat preservation stage of 200℃-300℃ is 1×10⁻⁶. -2 Pa-1×10 -1 The vacuum degree is 1×10 Pa during the heat preservation stages of 350-400℃ and 800-1000℃. -3 Below Pa.

7. The method for preparing copper alloy powder according to claim 1, characterized in that, In step S1, the concentration of the silane coupling agent is 10%-15%, the concentration of the titanate coupling agent is 2%-5%, and / or the pH of the passivation solution is adjusted to 4-6.

8. The method for preparing copper alloy powder according to claim 7, characterized in that, In step S1, the silane coupling agent is one or both of aminosilane and vinylsilane; the titanate coupling agent is a monoalkoxy titanate.

9. The method for preparing copper alloy powder according to claim 1, characterized in that, In step S1, the copper alloy powder body contains the following elements in the following mass percentages: Cu, Cr, Zr, Al, Ni and Mo: Cr: 0.8%-2.5%, Zr: 0.05%-0.5%, Al: 0.1%-0.8%, Ni: 0.2%-1.5%, Mo: 0.2%-1.5%, with the balance being copper and unavoidable impurities.

10. A copper alloy powder, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.

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